The son of one of Britain's most senior army officers has been severely injured in a roadside bomb blast in Afghanistan, it was reported today.

Captain Harry Parker, 26, is reported to have lost a leg in the blast and surgeons believe he may lose the other one. He has been flown back to Britain where he is being treated at Selly Oak Hospital in Birmingham and is understood to be very seriously ill.

His father, Sir Nick Parker, the Army's third most senior officer, returned from holiday after learning of his son's injuries.

A military source said: "General Sir Nick, his wife and the whole family are understandably devastated by what has happened to Harry. The general understands the risk more than most but it is still an appalling thing for any parent to go through."

Gen Parker will become the most senior British officer in Afghanistan in September when he takes over as deputy commander of Nato forces.

Sir Nick Parker

His son was leading a foot patrol of the 4th Battalion The Rifles when he is believed to have trodden on a pressure pad which set off an improvised explosive device on Saturday morning in the Nad Ali area of Helmand in southern Afghanistan.

The death of another British soldier was announced today, bringing the number killed in Afghanistan this month to 18 and the military death toll since the conflict started in 2001 to 187.

The latest victim, from the Army's bomb disposal group, was killed while on patrol on yesterday ­afternoon.

Hundreds more British troops have been wounded, including many who have suffered serious injuries. Army medics say at least 157 soldiers were treated at the field hospital at Camp Bastion in Helmand province last week.

One told BBC radio: "The last few weeks have been an extremely busy period. There have been injuries like you've probably never seen or ­experienced." Britain's army chief General Sir Richard Dannatt has drawn up a "shopping list" of equipment to counter the threat of roadside bombs, including more helicopters to transport troops, which has been presented to Gordon Brown.

Outgoing Nato Secretary-General Jaap de Hoop Scheffer, stressed in a speech last night in London that the alliance must remain in Afghanistan and win the conflict despite the growing ­casualties.

Warning against abandoning the campaign, he said: "Al Qaeda would have a free run again, and their terrorist ambitions are global. Those who say we can defend against terrorism from home are burying their heads in the sand."

Before delivering his speech, Mr De Hoop Scheffer held talks in Downing Street with Gordon Brown, who has been accused of failing to provide sufficient funding for the forces.

The Prime Minister's spokesman said Mr Brown talked him through the current UK Operation Panther's Claw in central Helmand, while stressing the need for "further burden-sharing" by Nato allies.